chore: Consolidate error enums and use expect where possible

[adwk67]

Description

Part of stackabletech/issues#883

--- PASS: kuttl (200.16s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/cluster-operation_zookeeper-latest-3.9.5_openshift-false (51.82s)
        --- PASS: kuttl/harness/smoke_zookeeper-3.9.5_use-server-tls-true_use-client-auth-tls-true_openshift-false (94.22s)
        --- PASS: kuttl/harness/delete-rolegroup_zookeeper-3.9.5_openshift-false (119.03s)
        --- PASS: kuttl/harness/znode_zookeeper-latest-3.9.5_openshift-false (26.49s)
        --- PASS: kuttl/harness/logging_zookeeper-3.9.5_openshift-false (105.93s)
PASS

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[maltesander]

This one can panic now and should have a comment saying so?

[maltesander]

This one can panic now and should have a comment saying so?

[maltesander]

This is also used as a service name and as the first label of the FQDN, so it shouldbe a label with max 63 chars and no dots? This would affect the check above.

Suggested change

	let _ = ClusterName::IS_RFC_1123_SUBDOMAIN_NAME;
	let _ = ClusterName::IS_RFC_1035_LABEL_NAME;

[siegfriedweber]

I would just document that the returned ListenerName is an RFC 1035 label name and create a unit test:

diff --git a/rust/operator-binary/src/crd/mod.rs b/rust/operator-binary/src/crd/mod.rs
index d2df7a1..fc81e09 100644
--- a/rust/operator-binary/src/crd/mod.rs
+++ b/rust/operator-binary/src/crd/mod.rs
@@ -50,6 +50,8 @@ pub mod tls;
 ///
 /// Lives in the `crd` module (rather than the controller build tree) because it is shared by both
 /// controllers and by [`role_listener_fqdn`].
+///
+/// The returned ListenerName is a lowercase RFC 1035 label name (checked by a unit test).
 pub fn role_listener_name(cluster_name: &ClusterName, zk_role: &ZookeeperRole) -> ListenerName {
     const _: () = assert!(
         ClusterName::MAX_LENGTH + 1 /* dash */ + RoleName::MAX_LENGTH <= ListenerName::MAX_LENGTH,
@@ -340,7 +342,7 @@ pub mod versioned {
     }
 }

-#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[derive(Clone, Debug, Eq, EnumIter, Hash, Ord, PartialEq, PartialOrd)]
 pub enum ZookeeperRole {
     Server,
 }
@@ -478,6 +480,7 @@ mod tests {
     use stackable_operator::{
         commons::networking::DomainName, versioned::test_utils::RoundtripTestData,
     };
+    use strum::IntoEnumIterator;

     use super::*;

@@ -774,4 +777,22 @@ mod tests {
             .expect("Failed to parse ZookeeperZnodeSpec YAML")
         }
     }
+
+    #[test]
+    fn role_listener_name_is_rfc_1035_label_name() {
+        // Every ClusterName is a valid RFC 1035 label name, so we use just some string with maximum
+        // length.
+        let _ = ClusterName::IS_RFC_1035_LABEL_NAME;
+        let cluster_name = ClusterName::from_str_unsafe(&"a".repeat(ClusterName::MAX_LENGTH));
+
+        for role in ZookeeperRole::iter() {
+            let role_listener_name = role_listener_name(&cluster_name, &role);
+            assert!(
+                stackable_operator::validation::is_lowercase_rfc_1035_label(
+                    role_listener_name.as_ref()
+                )
+                .is_ok()
+            );
+        }
+    }
 }

[maltesander]

Just nits, Changelog is missing.